package com.awakening.preset;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.*;
import io.netty.handler.timeout.IdleStateEvent;
import io.netty.handler.timeout.IdleStateHandler;
import io.netty.util.CharsetUtil;

import java.util.concurrent.TimeUnit;

/**
 * @Author:AwakeningCode
 * @Date: Created in 11:13 2018\3\9 0009
 */
public class IdleStateHandlerInitializer extends ChannelInitializer<Channel>{
    @Override
    protected void initChannel(Channel ch) throws Exception {
        ChannelPipeline pipeline = ch.pipeline();
        //IdleStateHandler将在被触发时发送一个IdleStateEvent事件
        pipeline.addLast(new IdleStateHandler(0,0,60, TimeUnit.SECONDS));
        pipeline.addLast(new HeartbeatHandler());
    }

    //实现userEventTriggered方法以发送心跳消息
    public static final class HeartbeatHandler extends ChannelInboundHandlerAdapter{
        private static final ByteBuf HEARTBEAT_SEQUENCE =
                //发送到远程节点的心跳消息
                Unpooled.unreleasableBuffer(Unpooled.copiedBuffer("HEARTBEAT", CharsetUtil.ISO_8859_1));

        @Override
        public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
            //发送心跳消息，并在发送失败时关闭该连接
            if (evt instanceof IdleStateEvent){
                ctx.writeAndFlush(HEARTBEAT_SEQUENCE.duplicate())
                        .addListener(ChannelFutureListener.CLOSE_ON_FAILURE);
            } else {
                super.userEventTriggered(ctx, evt);
            }
        }
    }
}
